Across the world, scientists are trying to determine where seasons are shifting. Spring arriving earlier, winter arriving later — it's happening in many countries. Now, the question is, what will be the consequences of that change.

The shifting of the seasons as the world warms up is putting a new focus on the field of phenology. As The World's Clark Boyd reports, scientists are trying to track winners, losers and ecological relationships that are getting out of whack.

The shifting of the seasons as the world warms up is putting a new focus on the field of phenology. As The World's Clark Boyd reports, scientists are trying to track winners, losers and ecological relationships that are getting out of whack.

Across the world, scientists are trying to determine where seasons are shifting. Spring arriving earlier, winter arriving later — it's happening in many countries. Now, the question is, what will be the consequences of that change.